Multicolor cinematograph and other film and process of making same



NOV. l2, 1929. J, E, THORNTQN 1,735,813

IJIIULTICIZIOR` CINEMATOGRAPH AND OTHER FILM AND PROCESS-OF MAKING SAME O Iiginal Filed May 5, 1924 i 2 Sheets sheet 1 llllllllllIlllllllllllllllllllll .ummmuuuuunnnuulg uu||||u|||||||||||||||||||g mmmwmmmw IllllllllllllllllllllllllllllllE- /uwree 0rd rye-ye//oh/ All NOV. l2, 1929. J, E THORNTON 1,735,813

MULTIGOLOR CINEMATOGRPH AND OTHER FILM AND PROCESS 0F MAKING SAME Original Filed May 5, 1924 2 Sheets-Sheet 2 Hman-Hed and /Mev- V/a ella/1d Patented Nov., y12, 1929 UNITED STATES- JOHN EDWARD THORNTON, 0F WEST HAMIESTEAD, LONIBN; ENGLAND MULTIcoLon cmnmamoennrn AND ornnn FILM Nn rnocnss ,or MAKING sum original application med may 5, 1924, serial-No. 711,254, and in Great Britain rmay 1s, 1923. Divide-a and this application led November 3, 1925. Serial No. 66,604.

Applications for this patent have been filed in'Great Britain, No. 13,358 of 1923, 4,009 of 1924, and 18,168 of 1924, all dated May 18, 1923.

This .invention relates to the manufacture and production of multi-color cinematograph and otherfilm negatives either in four or three colors.

The purpose of the present invention .is to' produce a complete color-group or unit of primary images of the original sub]ect, and similar color-group or unit of secondary images reproduced from the first, 1n order that such primary or secondary images can be used as printing clichs for producing similar multi-color positives.

This is effected by s litting the light coming from the object p otographed into two images of identical size by means of camera and suitable optical devices, -and receiving these two images upon a sensitized material of vspecial type, which is of double-picturearea and is provided with two screen-filters each containing a different pair of colors; the result being that two half-picture images are formed on the sensitive material which each represent an analysis of two colors only, the complete group being so constructed that 1t may comprise either four or three color-anal ysis resultingfrom the analysis provided by the two half-picture images.

In a co-pending application Serial No. 711,254, filed May 5, 1924 of which this application is a division, a method is described whereby the two half-pictures orsplit -records formed by this invention are reproduced as two positives of similar type, and-these two positives are then superimposed; and cemented together, so that they produce a reconstructed single picture (also. containing four or three colors as desired) which corresponds in character and in Icoloring to the original subject photographed.

This specification describes in detail the several steps required to produce -the negatives (preferably terms printing-clichs) from which those positives of similar type are produced. I

But negatives or printing-clichs of this double-screen type are not necessarily reexposure, four-color positive stricted to the production only of positives of the double-screen type, for they Vcan, be usedv starting point from which a set of four or three full-tone negatives can be reproduced,

each representingan analysis of only one color of the group.

Their widest application will no-doubt be found in producing, .by only one printingtransparencies in the form of thin or thick lms, glass plates, lantern-slides, cinematograph films and the like, upon sensitized positive-material which is of similar construction to the negative-material; that is to say which is also of doublearea, is provided with two screen-filters each representing a diierent pair of colors, and is covered twith a panchr matic` gelatinosilver emulsion.

By the use of these double area doublescreen negatives, and projection-printing' on to double-area double-screen sensitized positive-material, all the principal difficul- .ties in producing multi-color pictures "are overcome; 1t only be1ng necessary to cut, su-

perimpose and cement the two half-picture positives to produce a complete multi-color p1cture. f

The invention can be used with any optical system of lenses capable of producing two adjacent images of one subject, such for examplea pair of lenses; but the vpreferred form of optical system', whereby two images of the same subject are simultaneously ,formed upon the one film-strip and both photographed .from the same -viewpoint without showing parallax or fringing eiects, uses only one lens and a light-splitting device, and is fully described in a further application Serial No. 66,602 filed November 3, 1925.

In the drawings Fig. 1 shows a portion of a double width strip of transparent support upon which are formed two' screen iilters each having two colors as shown and formed of interspersed fine lines of different colors.

Fig. 2 is a similar View but with screens only analyzing three colors.

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`Fig. 3 is a similar view to Fig. l with screens formed of grains.

Fig. 4 is a similar view to Fig. QWith screens formed of gra-ins.

Fig. 5 is a similar View to Fig. 1 in which dots form one element of each screen.

Fig. 6 is a similar view to Fig. A2in which dots` form onel element of each screen.

Fig.7 is a section of a double width screen film negative material having a thick celluloid support, substratum layer', a pair of two color filters and a pair of black silver primary images of negative character.

Fig. 8 shows in section, a double width screen film negative material with a pair of secondary images.

Fig. 9 shows a piece of double width film containing a conventional design.

In all the above drawings the lines and dots are shown very coarse and wide apart for clearness of illustration, but in practice are exceedingly fine, the lins being preferably about 500 to the inch and grains finer still. ,Also the two groups of colors would partially overlap and mix in an actual picture but for clearness they yare shown in the diagrams as not overlapping. l

For producing non-cinematograph pictures the pair of negatives are formed upon adjacent areas of the sensitive-material arranged in vertical pairs or horizontal pairs.

A double-width negative nlm-material upon which the pairs of color-screens are arranged side-by-side in two rows is employeda The mention applz'ed to cinematography Structure of the negati/ve )ihn-material The following is a brief and general description of the negative film-materialf a more detailed description of which and methl known as screen film.

` od of its manufacture is given in application Serial No. 66,603, filed November 3, 1925.

The special film-material upon which the negatives are` photographed is ofv the .class By this is 'meant upon the face/of the celluloid "'(oralternatively it may be printed direct upon the celluloid itself), and this screen is afterwards covered with a panchromatic gelatino-silver-bromide emulsion. But in this invention a special form of screen-film is used which is provided with a pair of screens (each different) .instead ofv the usual -single type'of screen; lwhich are hereinafter more fully' described.

The base used for the negative film is preferably'of the full standard thickness (about .0045 inch) .(Figures 7 and 8), and when the substratum, screens, and sensitized layer are added the total thickness of the negative film is about .0065 inch."

Exposure of this negative film in the camera is made with the transparent base of celluloid or other material facing towards the lens and the sensitized side turned away from the lens, so that light passes first through the transparent base, then through'the pair of screens r light-filters, and finally reaches the panc romatic emulsion, upon which vit forms` a pair of section-images each ,representing a different pair of color-sensations according to the colors of the light which theyfilters have allowed to pass.

For four color negati/ves V I exceedingly (Figures l, 3 and 5), a` fuller description of Whlch 1s given in the aforesaid specification Serial N o. 66,603. These are arranged in two groups,-.sidebyside upon the two halves of Y the double-width film strip (Figures 7 and 8). One screen consists ofl dots, lines or other pattern of two colors equally intermiXed, and the other screen of two other colors equally intermixed. The colors used for a four-color screen-filterl set are `preferably 'crimson-red and blue-green fork one half of the double-width negative film, and, blueviolet and orange-yellow for the other half. These form one filter-set containing the complementary colors of'red and green, and another filter-set containing the complimentary colors of blue 'and yellow. Each half of the double-width film therefore contains its own complementary color, and the two halves are also complementary to each other. This particular arrangement however is not necessarthough 1t 1s preferred,

ily a hard land fast rule, for if desiredv the complementary colors of each pair may be arranged upon the adjoining half-widthv half-Width.

For three-color egdtz'vs. i

instead of upon the same The filter-screens forpthree-'color'are of a i that the transparent celluloid base is provided `similar character (Figures 2,-'4 and 6), con- Awith acolorfilter in the form of a very fine multi-'colored screen (Figures 1 to 6) printed l or formed upon a substratum amalgamated sisting of fine dots, lines, or mosaic pattern,

but the colors comprise only crimson-red2 l blue-green, and blue-violet. They 'are ar` ranged in two groups, one upon each half of the double-width film as in t e preceding example, but one of the colors is repeated upon each half. For example one half-width may have a filter-screen of crimson-red and bluegreen, and the other a filter-screen of blueviolet and blue-green. Or any other preferr-ed arrangement of the combination may be used; for instance by duplicating the yellow filters on the negative-film the complementary color, blue-green, will predominate in the positive film because it will be repeated upon both halves.

Producing the original (camera) negati/vee ing clich until the .black images have been reversed as hereinafter described.

The camera and optical light-splitting arrangements are so constructed that, when a strip of such double-width color-filter screenfilm is exposed therein, the primary iinage formed by the onelens is split into two sec` ondary images by means of the light splitting device, and thus two separate images are simultaneously formed upon the two halves of one film, as more fully described in the copending specification Serial No. 711,254.

If the negative material is of the four-color type each of these images will be again divided by its filter, so that the double-width film will then carry two half-picture negatives side-by-side u on the same film (each recording two colors making fourrecords of different color-sensations on the one doublel' width film-strip.

It the negative material is ofthe special three-color type already described .the result will be similar, except that one of the colorsensations will be repeated upon both halves l of the double-width.

v' Producing the printing clichs Having made the camera exposure eand o'b- 's' tained the original negative-records by the method described, it is now necessary to roduce a printing-clich from which the nal positive-records (Figure 8) for exhibitioncan be printed. At this stage .therefore (A) The. (which .is complementary in its coloring tov the actual scene photographed) may be usedto produce a corrected Vpositive by printing. i I

from the original negative through alens'oli to a positive film of similar character, alsoi l provided'withf'similar color filters and panchromatic emulsion, in which case the colors on the resulting positive will be again kreversed and therefore will be the same as those in the original scene or object.

(B) The original (camera) negative may be treated by the usual reversal bathsand `treatment by which it can be converted from a negative of .incorrect or complementary col- .ors into a positive of correct or non-comple-l mentary colors, so that the real coloring of tnhe scene or object is produced on the original lm. 'f

' (C) A positive in black and whitoe can'be i reproduced from the colored negative A, or a negative `in black and white can be reproduced from'th colored positive B, by copying through a lens and camera.

The term printing-clich is used to cover either the negative or positive form of reproduction matrix. ,f

A printing clich of the black and white type such as C, reproduced from colored nega-' tive A or--colored positive-B, may be used for direct-printing either by contacter by projection -upon any of thedi'erent types of sensitized material. lSuch a printing-clich is best produced from a large projected image by copying, the printing clich for each 'of the four colors being photographed separately through color filters which cut out all but the one color to be-reproduced.

Or a-.positive of correct colors such as B may be againused to negative like the original complementary one.

A certain slight loss or degradation off color occurs with every reproduction, but the amount is not a serious objection in this invention.

Preferred form of printf/rig-clichs produce a duplicate .iio

Of these several methods it is preferred in commercialv manufacture not to use the original (camera) negative, because of the labour involved in treating continuous lengths of lxn to the processes of reversal and also because of the danger of damaging the original ne ative in the processes.

t is therefore preferred to make a reproduction from-the original, and further because by. makin such reproduction the necessary reversal 4o 'imageis simultaneously effected (Figure 7). Therefore a positive print is made from the original negative by copying in a'. camera through a lens and. de-

veloping the image in the usual way, inaccordance with method A. This will produce a copy in whichythe black-silver images will -be of positive character, and this co y is izo used as the printing-clich` from whic theA actual exhibition positives are reproduced.. 13

Therefore in these final reproductions for lexhibition urposes (produced according to the co-pendling application Serial No. 66,602 hereinbefore referred to) ,theblack-silver 5 images will be of negative character 'and the color-screens visible through them will be of positive character.

, What I" claim as m invention and desire f tfprotect by-Lette'rs atent is rnulti-color screen-mosaic picture-negative comprising a transparent support of doub1epicture-'area, a two-color mosaic filterscreen...upon one area of the support and another two-color mosaic filter-screen u on another area of the support, the two-co ors in one screen being different from the two col# ors 'in the other lscreen, the support bearin one component-image behind one screen an another component-image behind the other 2o screen, each component-image being diferentl from the other` one compartment-image I and its lter-screen comprising one half-picture and the other component-image and its.

. filter-screen comprising the other half-pic ture.

2.- Thevpro'cess f producing a multi-color screen-mosaic picture-negative which comprises projectin ima es of an object on to a sensitized me ium rough apair o'ftwo- 39 color mosaicfilter-screens arranged side by side, the .colors in one 'screen being different from the colors in another screen, whereby component-images are formed on the sensitized medirm behind the respective screens.

In testimony whereof I have hereunto set my hand.

JOHN EDWARD THORNTON. 

